Combustion apparatus for furnaces.



No. 758,404. PATENTED APR. 26, 1904.

v. ZANETTI.

COMBUSTION APPARATUS FOR FURNACES.

APPLICATION FILED NOV. 28, 1903. no MODEL. 2 SHEETS-SHEET 1.

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No. 758,404. V I .PATENTED APR. 26, 1904. v

- V. ZANETTI.

COMBUSTION APPARATUS FOR FURNACES.

APPLICATION FILED NOV. 2a, 1903.

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- Patented April 26, 1904.

PATENT OFFICE.

vINoENzo ZANETTI, or GENOA, ITALY;

COMBUSTION APPARATUS FOR FURNACES- SPECIFICATION forming part of Letters Patent No. 758,404, dated April 26, 1904. Application filed Novei'mber 28,1903. Serial No. 182,958. (No model.)

To all whom it may concern.-

Be it known that I, VINoENzo ZANETTI, a subject of the King of Italy,residing at Genoa, Italy, have invented a new and useful Improvement in Combustion Apparatus for Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the same.

The present invention refers to a rational system of combustion in the furnaces of steamboilers with .a view to utilizing completely all the heat developed by the fuel.

The low percentage of useful result obtained in practice from. the fuel burned in the furnaces of steam-boilers depends principally upon the wasteful absorption of heat due to the fact that the temperature of the nitrogen contained-in the atmospheric air introduced must be elevated to the temperature of the surrounding gases and also from the great ra-- pidity with which the products of combustion pass through the tines into the-smoke stack; also, further, from thedeficiency of air mixed with the unburned gases, and, finally,

from the fact that the rapid passage of com-.

bustible gases through surrounding strata of lower temperature prevents the gases from burning completely; Inorder to eliminate these causes that oppose the regular development of the combustion and to obtain a greater utilization of heat, I proceed upon the theory that the gases in their flight to the smokestack should meet with a slight obstacle. This not only retards their progress, but when said obstacle is made incandescent by the passing flames, as in my invention, it favors the gasification of the combustible particles carried by the passing currents, and this is further promoted by a convenient jet of air introduced at this point to complete combustion. To this effect I disp'osein a convenient position in the passage-way between the furnace and the smokestack a reticulated diaphragm composed of one or more metallic nets covered with special substances adapted to become incandescent without burning, and I also provide a perforated air pipe or pipes adapted to conduct air from the outside to the interior of the steam- -boiler furnace at a convenient point on this diaphragm in order to cause theburning of the said gases.

The invention is shown in the accompanying drawings, where- Figure 1 represents across-section of a tubular return-flue boiler provided with my invention, with the half to the right on the line A B C D E F of Fig. 2 and with the half to the left on the line G H I J K L of the same figure. Fig. 2 is a longitudinal section on the line M N of Fig. 1; and Fig. 3 is a detail View of a portion of the Wire net at, showinga part of the wire bare and a part covered with its The network a is preferably made as follows: Its meshes are formed of interwoven wires coated with amianthus fibers (fineasbestos) mixed with potassium or sodium silicate, graphite, potato-starch, and glue solution of any kind or with other equivalent material adapted to be retained on the wires and to become incandescent. It will be seen that the superficial coating forthe wires is composed of refractory ingredients combined with binder ingredients to hold them onto the wires, so that the coating will remain on the wires, and thus serve the double purpose of protecting them against destruction and maintain incandescence. After having woven the net this latter is out according to the size of the place in which it is to be applied. The said net may be either'plane, concave, or'convex or of any other convenient form. As to the thickness of the wires, the width of the meshes, and the form of the net, of the bindings and supports to keep it in place, this de-' pends upon the particular application made. In this matter special attention should be given to the intensity of the combustion and the place in which the said net is to be arranged. In the application shown in the drawings the net to is disposed diagonally in' a, it will be seen, forms a complete diaphragm, through which the gases and products of combustion have to pass on their way from the fire-box to the smoke-stack.

Air is introduced through the tube (or tubes) f, which is closed at its ends and perforated along its surfaces. These tubes are arranged horizontally above and adjacent to the network a and communicate with the atmosphere by means of tubes 9 and It, the first of which, g, are disposed horizontally among the boiler-tubes and extend to the front, while the tubes [L are arranged vertically and located in the smoke-box at the front and extend downwardly and communicate with the outer air, so as to establish communication from the interior of the perforated tube f and the chamber e to the outer air. The fresh air introduced at the diaphragm serves to burn the unconsumed particles and prevents the clogging of the diaphragm, so that the draft of the furnace is not obstructed. The air-tubes might, however, be situated in any other convenient position adapted to obtain the same results.

The tubes h are provided, preferably at i or at any other convenient place, with a valve operated from the outside and adapted to regulate the quantity of air that is to be introduced into the fire-box.

It is to be understood that these parts of the apparatus, with their accessories, are to be considered merely one example of my invention. Many variations in form, dimension, and disposition may be made to suit different applications of the invention. It is also to be understood that my invention may be applied not only to the return-flue boiler, as shown, but also to any other kind of boiler.

As already stated, the practical results of this invention are to increase greatly the percentage of heat from the fuel used for steamboilers and to diminish or to eliminate altogether the soot and smoke, which are almost completely burned by means of a convenient regulation of the ratio between the air introduced through the ash-box and the introduced through the air-tubes f, the smoke and soot being already heated up by the incandescing net through which they passed, and as the velocity of their flight to the smokestack is considerably diminished by the said net the combustion of the gases and utilization of heat in the boiler are greatly promoted.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A steam-boiler furnace having located in the passage-way between the fire-box and the smoke-stack a reticulated wire diaphragm through which the gases have to pass, said diaphragm-wires being superficially coated with refractory materialto protect the wires and maintain incandescence substantially as and for the purposes described.

2. A steam-boiler furnace having located in the passage-Way between the fire-box and the smoke-stack a reticulated wire diaphragm, through which the gases have to pass, said diaphragm-wires being superficially coated with refractory material to protect the wires and maintain incandescence, and a perforated airinlet pipe located immediately adjacent to the reticulated diaphragm to burn the unconsumed particles and keep the diaphragm from clogging substantially as described.

3. A reticulated and incandescing diaphragm for a steam-boiler furnace, composed of a network of wire having a superficial coating of refractory mineral ingredients combined with a cementing-binder to maintain the adhesion of the coating and the complete covering and protection of the wires substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

VINCENZO ZANETTI. Witnesses:

ANTONIO MORTI, A. FERRATI. 

